Latch mechanism



Feb. 16, 1960 J. PICKLES LATCH MECHANISM 2 Sheets-Sheet 1 Filed Feb.v 7,1955 NQE MS E ML K VG WP H P E S O J 17%; ATTORNEYS Feb. 16, 1960 J.PICKLES Q 5,297

LATCH MECHANISM Filed Feb. "7, 1955 2 Sheets-Sheet 2 INVENTOR. JOS-IEPHPICKLES Q 7 BY W ATTORNEY From an inspection of Figure 5 it will beapparent that the wedge portion 44 of the element 40 is effective toprevent counterclockwise rotation of the rotor 10. It will also beapparent that forces tending to rotate the rotor counterclockwiseproduce camming forces tending to swing the wedge cam element 40 in acounterclockwise direction. However, such movement ofthe wedge camelement 40 is frictionally opposed by the friction between the fixedabutment 56 and the ar'cuate surface 54, as well as the frictionalforces existing between the lobe surface 32 and the camming surface 46of the wedge cam element 40. Since both of these frictional forcesoppose camming of the wedge cam element 40 in a direction to release therotor 10, it will be apparent that the included angle between thesurfaces Y46 and 54 considered as a wedge may have a value substantiallytwice as great as the angle of repose for the materials of which theabutment 56, surface 54, surface 46, and surface 32 are formed. Thispermits a relatively great cam rise on the cam surface 46 for acorrespondingly small angular movement of the arm 42.

As previously indicated, the surface 34 of the lobe is shapeddifferently from the involute side 32 thereof. The wedge cam device 40is provided with a surface portion 58 cooperable with the side 34 andparticularly the tip 60 of the lobes so that upon rotation of the rotor10 in the direction resulting from'movement of the, lobe into latchedposition, the lobe rocks the wedge cam element 40 out of latchingposition. 7

By properly selecting the angular orientation of the lobes 30 withreference to the teeth 12, an arrangement results in which the latchrotor 10 cams the wedge cam device out of blocking position as the teeth12 roll over the teeth 22 of the keeper until the housing 14 reaches thepositionillustrated in Figure 6. 'If the door is not completely closedso that the wall portion 24v of the housingis spaced from the end wall26 of the recess in the keeper, the latch will operate to preventopening movement of the door. If the door is thereafter caused to moveby small increments, such for example as by vibration, further towardfully closed position, suitable spring means bearing against the wedgecam device 40 cause it to follow up so as to prevent return motion ofthe latch rotor from the furtherest latched position which it reaches.

Referring now to a practical embodiment of the invention, theconstruction comprises an angular support plate 62 having a wall 64normally disposed at the free edge of a door, and a wall 66 disposed atone side of the door. Where the latch mechanism is used in conjunctionwith an automobile, the wall 66 is normally located at the inner surfaceof the door. The wall 64 includes a rearwardly extending flange portion68 to which is secured suitable lock mechanism indicated generally at 70and, includes an actuator 72 for release of the latch as willsubsequently appear.

The toothed portion of the latch rotor including the teeth 12 ispartially housed within the housing 14 previously referred to, whichhousing includes a mounting flange 74 welded or otherwise secured as.indicated at 76 to the outer surface of the plate 64. At the oppositeside of the plate 64 from the toothed portion of the rotor 10 isprovided the lobe portion thereof having the lobes 30, as best seen inFigure 1. Mounted in the plane of the portion of the rotor containingthe lobes 30 is a lever or arm 78, this arm being mounted for rotationabout a pin 80 and including an enlarged opening providing for somefreedom of 'movement of the arm 78 in a direction perpendicular to theaxis of the .pin 80. The arm 78 is provided with an arcuate slot 82through which extends a fixed abutment pin 84. A spring 86 is providedsurrounding the pinf80 and includes, an end portion 88 engageable with alaterally bent flange 90 on the arm 78, With the parts in the positionillustrated in Figure 1, 1

the portion of the lever intermediate the lobe 30 and the fixed abutment84. The camming surface 92 of the arm 78 engages the involute surface 94of the lobe 30.

In order to free the rotor 10 for the free rotation required to move thedoor to open position, the arm 78 is rockedin a clockwise direction, asseen in Figure l for example by pressure applied against the flange 90.In the practical door construction the flange may be engaged by suitableactuating means such as a handle controlled lever or push button at theoutside ofthe door.

The spring 88 is effective to cause the camming surface 92 of the wedgecam element 78 to follow up any movement of the lobes 30 of the rotor.

As is customary in automobile door latches, additional means areprovided for actuating the latch release mechanism. This means comprisesan actuating lever pivoted to the plate 66 as indicated at 102. Thelever 100 includes a projection 104 movable into the path of a hookshaped portion 106 on the wedge cam arm 78 so as to blockmovement of thearm 78 to latch release position. The lever 100 is provided with anopening 108 receiving one end of the key actuated crank 72. The lever100 includes a projecting arm 110 which overlies the hook portion 106 ofthe wedge cam arm 78 so that the wedge cam arm 78 may be moved to latchrelease position by swinging movement of the actuating lever 100. Thelever 100 includes the elongated slot 112 forconnection with the usualpush button actuator provided on automobile doors, by means of which thelever 100 may be moved into and out of position to block releasemovement of the wedge cam arm 78.

From the foregoing description it will be apparent that when mounted onthe edge of a door as previously in dicated for coaction with the keeperplate as indicated in Figure 6, the door may be slammed shut which willresult in rotation of the latch teeth 12 relative to the stationary rackteeth 22 of thekeeper plate. This rotationof the latch rotor 10automatically shifts the wedge camv arm 78 out of wedging position, butthe wedge cam arm. moves back to wedging position under the influence ofthe spring 86 as soon as the door is closed. The wedging action fo thewedge cam arm prevents any slight reverse rotation of the latching teethand since the spring continues to'urge the wedge cam arm in wedgingdirection, it will follow up any further additional incrementalmovements in rotation of the latching teeth if the door moves slightlyfurther toward latched position. In order to open the door it isnecessary to release the wedge cam arm and this may be accomplished byswinging the wedge cam arm 78 in clockwise direction, as seen inFigure 1. This may be accomplished by pressing on the flange 90 of theaim through suitable outside handle mechanism or by inside remotecontrol handle mechanism coupled to an opening indicated at 114 in thelever 100.

Referring now to Figures 6 and 7 there is illustrated an arrangement inwhich the latching teeth 12 are helical further be observed that due tothe inclined relationship of the latch teeth 12 and the engaged tooth 22of the keeper, movement of the tooth 12 (and hence of the entire latchmechanism) relative to the keeper in the direction of'the arrows 118 iseffectively prevented, As a result of this construction theinter-engagement be tween the latching teeth of the latch rotor andkeeper.

p es fi m n e ti e een h 49st and frame at.

the vehiclelongitudinally of rev-chat. r ass-mat of this thedoorwhecome's a srtuctu l ;partj: f the vehicle frame a H Theexaethelix'angle 'ofth the, teeth 22 is not critical except that, in ,fordertoretain a firm andieifect'ive' engagement, the angle should .besubstarltial. It will of "sense be'apparlen'tj that if the teeth 1 12 ofthe latch rotor have'a helix angleof zero ,,de'grees, they willhaveiio'elfect v'v'hatv'e door to take uplongitudinalstresses,ibiitfwill be'perfectly effective to retain thedoof'inlat'ched position. At the other' extreme, the helix angle of theteethtcannot be e [or an gnlarity of mean and one'of 'which' includes afixea iacnag projecf rotor having 'a radially extending lockingprojection movablefover and engageable with the smear said fixed lock 7ing projection at the closed inner end of said 'rec'essfthe too largesince clo'singrnove'm'entof' the door isfrequir'ed I to producerotationof the? 'latch ro tor For practical purposes the helix angle'ofthe teeth 12 on the rotor will normally be between 30 degrees and 60degrees. Itwill of course be apparent that the hand of the teeth 12 andthe direction of inclination of the teeth 22 are required to conform andwill be in the direction such that engagement between a single tooth 12and a single tooth 22 is effective to oppose both ope'ningmovement ofthe door and longitudinal separation between the free edgeof the doorand the adjacent portion of the door opening.

The drawings and the foregoing specification constitute a description ofthe improved latch mechanism in such full, clear, concise and exacttermsas to enable any person skilled in the art to practice theinvention, the scope of which is indicated by the appended claims.

What I claim as my invention is': v

1.- Door latch mechanism for connecting the free edge of a swinging doorand a door frame in which the door is pivotally mounted comprising acooperating rotor and keeper releasably connecting the free edge of thedoor and the frame and including means for selectively preventingrotation of the rotor in the directionrequiredto permit opening movementof the door from latched posi-- tion, said rotor being disposedwith itsaxis generally parallel to the plane of the door when the door closed,said keeper comprising meansdefi ninga generally .hori-'- zontal recessextending in a direction transverse to the ra so nsagi c'surfa e 'o'n sh s e r u faces of said "locking projections, and the engaging'surfacesof said keeper at the closed inner end of its recess and the surface ofsaid rotor housing at the side of said rotor, converging toward the freeedge of the door to' l prevent separation between the free edge ofthedoor and the adjacent edge of the door frame ina direction parallel tothe plane of the door when closed.

3. Door'latch mechanism for connecting the free edge of a' swinging doorand a door frame in which the door is pivotally mounted comprising acooperating rotor and keeper releasably-connecting the freeedge of thedoor and the frame and including means for selectively preventingrotation of the'rotor in the direction required to permit openingmovement of the door from latched position, said rotor being disposedwith'its axis generally parallel to the plane of the door when the dooris closed, said keeper comprising means defining a generally horizontalrecess extending in a direction transverse to the plane of the door whenthe door is closed and having a pair of vertically separated surfacesone of which is smooth and one ofwhich includes a plurality of fixedlocking projections plane of the door when'the door is closed and having2 7 upper and lower surfaces, said .recess being open at one end toreceive said rotor and closed at its other end to provide an abutmentsurface, said 'keeper havinginsaid recess a fixed locking projection,said rotor having a, housing having a generally horizontal wallengagingone of said-upper and lower surfaces of the recess in saidkeeper I and having at one side ofthe rotor a surface'engageable withthe abutment surface of the recess in said keeper to limit closingmovement'of the door, said rotor having a radially extending lockingprojection movable over and i engageable with the side of said fixedlocking projection at the closed inner end of said recess, the pairs'ofengaging surfaces consisting of the engaging surfaces of' a said lockingprojections, and the engaging surfaces of a said keeper at the closedinner end of itsrecess and the surface of said rotor housingat the sideof said rotor, converging toward the free. edgeof the doorjto preventseparation between thefree edge of the demand the adjacent edge of thedoor frame in a direction parallel to the plane of the door when closed.

a I i 2. Door latch mechanism for. connecting thefree edge of a swingingdoor and a door frame in which the'door is pivotally mountedcomprisingfa cooperating rotor and keeper releasably connecting the freeedge of the door and the frame and including means for selectivelypretion, said rotor being disposed with its axis generally parallel tothe plane of the door when the door is closed,

ering said rotor and having a first wall providing a surface I slidableover the smooth surface of said'keepcr and a second wall providing anabutment surface engageable. with the abutment surface of said recess tolimit closing movement of the door, said rotor having radiallyextending'locking projections movable over and engageable I with theside of said fixed locking projections at the closed inner end of saidrecess, the pairs of engaging surfaces consisting of the engagingsurfaces of said locking projections, and the engaging surfaces ofsaidkeeper at the closed inner end of its recess and the surface of saidrotor 'housingat the side of said rotor, converging toward the 1 freeedge of the door to preventfseparationhetween the freeedge of the doorand the adjacentedge of the door frame in a direction parallelto theplane of the door when a closed. 1

4. Door latch mechanism for connecting the free edge of a swinging doorand a door frame in which the door is pivotally mounted comprising acooperating rotor and keeper releasably connecting the free edge of thedoor and the frame and including means for selectively prerventing-rotation of'therotor in the direction required to permit openingmovement of the door from latched p osition, said rotor being disposedwith its axis generally parallelto the plane of the door when the dooris closed, said '1 keeper comprising means defining a, generallyhorizontal recess extending in a direction transverseto the plane of,'the'door when the door is closed and having upper and lower-surfaces,said recess being open at one end to resaid keeper comprising meansdefining a generally horipair of vertically separated surfaces one ofwhich is ceive said rotor, abutment means acting between said door anddoor frame and having abutment surfaces disposed i generally-parallel'tothe plane of the 'door when the door is closed, said keeper having insaid recess a fixed locking projection, said rotor having a housinghaving a generally"? horizontal wall engaging one, ofsaid upper andlower 7 v surfaces of the recess in said keeper, said rotor having a j 1a radially extending locking projection movable overand V engageablewith the side of said fixed locking projection at the inner endofsaid-recesgthe pairs of engaging SUI? faces consisting of the engagingsurfaces of 'said' locking projections and the abutment surfaces of saidabutment means converging toward the free edge of the door to providewedge means operable to prevent separation between the free edge of thedoor and the adjacent edge of the doorframe in a direction parallel tothe plane of the door. when closed, and manually releasable take-upmechanisn 'operatively connected to said rotor and operable to preventunlatching rotation thereof from any position Withix'l a range ofdoor-latched positions as determined by engagement between the abutmentsurfaces of said abut? {Hint means.

-Reei-encesite nin file .Q Ib s pa n UNI ED STATES PATENTS Spore V May23, 1871 I Whitcbinb Feb. 24,1914 Benn tt-- J y 5 1916 Wells --V- Dec.3, 1929 Marple Apr. 23, 1940 ,Marple May 27, 1941 -Marp,1e r r Nov. 10,1942 Endter Mar. 23, 1943 Roethel V v Feb. 24, 1953

